Abstract:

The objective of the study was to establish to what extent the native tick species Rhipicephalus
decoloratus had been displaced by the invasive introduced tick, Rhipicephalus microplus at two
communally grazed areas in the Eastern Cape Province, South Africa. To this end ticks were collected
monthly from 5 cattle over a period of 2 years and from 10 drag-samples of the vegetation over a period
of one year at each locality. Whereas 10 years previously only R. decoloratus and no R. microplus had
been recorded in the vicinity of the two sites, R. microplus now comprised the bulk of collections at both.
Furthermore, significantly greater numbers of R. microplus were collected from cattle at both localities
during the 2nd year of the survey than during the 1st (P<0.05 and P<0.01). In addition to 83 instances of
intraspecific coupling, there were 17 instances of R. microplus males coupled with R. decoloratus
females. Collections made from cattle and goats on 2 farms close to the study sites revealed that R.
microplus was present on both host species and that it significantly outnumbered R. decoloratus on one of
the farms (P<0.001). R. decoloratus and R. microplus larvae as well as larvae exhibiting characteristics of
both species were collected from the vegetation.